Can anyone recommend a moderately priced amplifier for a Marantz SR8200 receiver? It has a built-in preamp and just wanted to know if anyone has a similar situation. That is, having an AV receiver with a preamp and an amp together. The SR8200 AV receiver does not have enough power to the speakers and just wanted additional amplification. Is it possible to add an amp to an AV receiver with a preamp?